Furniture units with drawers are generally well known in the art, and typically include multi-drawer vertical files, such as those used in freestanding file cabinets, pedestals for desks, worksurfaces, computer support units, and other similar furniture applications. When the drawers in such furniture units are to be used for relatively heavy articles, such as document storage, the unit is preferably provided with some type of drawer interlock mechanism that will permit only one of the drawers to be opened at any given time, so as to avoid vertical instability, tipping, etc. Such interlock mechanisms are normally provided as a safety feature in freestanding vertical files.
Many people find the interlock system annoying and inconvenient at times, because it prevents more than one drawer from being opened at any given time, even when potential tipping hazards or vertical stability problems are non-existent. For example, a furniture unit, such as a desk pedestal, having a lower 12" file drawer and one or two upper 3" personal drawers, is not likely to tip if one of the upper 3" drawers is open when the file drawer is already open. The user of a furniture unit of this type may desire access to the contents of one of the 3" personal drawers while the file drawer is already opened, such as to get a pen to make a notation in the file before returning it to the file drawer. With a conventional interlock system, the file drawer must be closed before the personal drawer can be opened to obtain access to the contents thereof, and the personal drawer must be closed before the file drawer can be reopened. In many cases, it would be much more convenient to be able to simply open the personal drawer, such as to remove a pen, without having to first close the file drawer.
One way in which a furniture unit could be provided with a plurality of drawers which can be opened at the same time would be to simple eliminate the interlock mechanism. However, because the drawer interlock mechanism of conventional lockable furniture units generally cooperates with, and is integrated to, the interlock mechanism, it would be necessary to provide alternative locking means if it is desired to convert an existing furniture unit having lockable, interlocked drawers, into a furniture unit having lockable, non-interlocked drawers (i.e., drawers which can be opened irrespective of whether or not another drawer is already open). The use of alternative locking means would be particularly undesirable in situations where a manufacturer intends to manufacture both an interlocking version, and a non-interlocking version of a lockable furniture unit at the same manufacturing plant or production line, because excessive alternative manufacturing equipment, manufacturing processes, and inventory of parts would be required for the alternative locking means. Accordingly, it would be desirable to provide a means or device which is capable of converting a lockable furniture unit having an interlocking mechanism (for preventing a second drawer from being opened when a first drawer is already open) into a lockable furniture unit which allows a second drawer to be opened when a first drawer is already open, and which cooperatively interacts with an existing drawer locking mechanism, whereby the need for additional alternative locking means is eliminated.
Known furniture units with a plurality of drawers have either been of the interlocking type, wherein only one drawer can be opened at any given time, or of the non-interlocking type, wherein any or all of the drawers can be opened at any given time. Heretofore, partially interlocking drawer systems wherein at least one drawer can be selectively opened irrespective of whether other drawers are already opened, and wherein at least one other selected drawer cannot be opened if at least a third drawer is already opened, have not been sold or otherwise disclosed, nor have advantages thereof been described. However, a partially interlocking drawer system may be advantageous for certain types of drawer configurations, such as where it might be undesirable to have two or more large file drawers of a furniture unit opened at the same time, yet acceptable and desirable to have a small drawer opened at the same time that a file drawer is open. Accordingly, it would be desirable to provide a means or device for providing a furniture unit having selectable non-interlocking drawers and selectable interlocking drawers. Further, it would be desirable to provide such means or device which would allow such furniture unit to be reconfigured as interlocking, non-interlocking, or partially interlocking, as desired.